Replacement of conventional cast iron disk-brakes with organic lining pads by their carbon-carbon equivalents creates a major difficulty in relation to the caliper, especially in wheeled vehicles. There are actually two problems:
The first relates to fixing the pad on the caliper. Since the way organic lining pads are made is very different from the way carbon-carbon pads are made, it is impossible to manufacture a carbon-carbon pad with the same structure as its organic equivalent. As a general rule, organic linings are molded on a metal plate (called a backplate) having means for fixing the pad. An identical carbon-carbon pad would require special processing.
The second problem relates to the thermal insulation of the caliper. For the same application, a carbon-carbon pad has a much higher operating temperature than its organic analog. Insulation is thus necessary to protect the caliper from excessive temperatures, which could lead in particular to the problem of a vapor lock affecting the caliper-actuating fluid.
For these reasons the usual caliper is replaced in practice by a special caliper designed for carbon-carbon lining pads and disks, especially in racing vehicles.
In order to effect the insulation, one such known caliper comprises insulating titanium or asbestos rings fitted on the ends of the pistons (or even pistons made entirely of titanium) and support lugs, likewise of titanium, mounted on the caliper for retaining the lining laterally.
Replacement of the original caliper by a different design of this type results in high installation costs for these brakes, which are more efficient than conventional brakes.